The Redrock Micro ultraCage Blue 19 mm Top Rail Clamp is an accessory for the ultraCage that adds 19 mm top rails onto any ultraCage system. The ultraCage already supports adding a 19 mm baseplate, so the 19 mm top rails are a nice way to standardize on 19 mm throughout the rig.
The 19 mm clamp connects to the top of the ultraCage and top handles are then attached to the 19 mm clamp. The 19 mm clamps can be used in single or double configuration, though often double-configuration is used in combination with the ultraCage blue rear chassis cage to create an incredibly solid full-sized support cage. Add a pair of Redrock 19 mm carbon fiber rails and you are ready for anything.